The NYSBC, a consortium of nine academic medical research institutions, proposes to construct a 10,000 sq. ft. addition to its existing facilities to house three state-of-the-art cryo EM. The objective is to expand the NYSBC's scientific scope, which currently focuses on magnetic resonance spectroscopy, by creating a resource and program in the complementary field of cryo EM. These new resources will serve a large, internationally-recognized community of National Institutes of Health (NIH)-funded biologists who do not currently have adequate (or any) institutional access to cryo EM. The proposed expansion will serve more than 25 research groups that use cryo EM directly, or in conjunction with crystallography and magnetic resonance spectroscopy, to study proteins and supramolecular machines. Another 40 researchers who do not currently use cryo EM, will be able to undertake more difficult problems in their fields with access to the integrated resources provided by the expanded NYSBC. The NYSBC is located on the campus of City College of New York (CCNY) at 133rd Street and Convent Avenue in Upper Manhattan. It is being constructed in three phases: 1) Phases I and II will house a group of high-field magnetic resonance spectrometers (750, 800 and 900 at MHz); Phase I will be operational by March 31, 2002; and Phase II will be operational by December 31, 2002. This application is for Phase III funding only. It comprises 10,000 sq. ft. to house three cryo EM at 120 kV, 200 kV, and 300 kV, and necessary ancillary activities.